Power Pulsation Decoupling in a Series-Stacked PV- Battery Inverter

Abstract

This paper presents the design of an energy buffer decoupling double-line-frequency AC power pulsation from main DC power sources in the single-phase series-stacked PV-battery inverter. As the active decoupling technique reducing the amount of capacitance required to stabilize the DC-bus voltage and achieving elimination of electrolytic capacitors, the series-stacked buffer architecture is adopted. In this work, the focus is on the optimization of the buffer design in the series-stacked PV-battery inverter and presenting the control scheme of the partial-power DC-DC optimizer to avoid processing the double-line-frequency AC current through all the DC sources: a PV string and a battery. The steady-state operation of the AC power pulsation decoupling of the series-stacked PV-battery inverter is demonstrated and verified through the controller hardware-in-the-loop test.